2, 6-dioxypyridine and acid addition salts thereof for dyeing human hair



United States Patent M 3,231,471 2,6-DIOXYPYREDINE AND ACID ADDITIQN SALTS THEREOF FOR DYEENG HUMAN HAER Fritz-Walter Lange, Hamburg-Grossflottbek, Germany assignor to Hans Schwarzkopf, Hambnrg-Aitoua,

Germany No Drawing. Filed Nov. 1, 1962, Ser. No. 234,863 Claims priority, application Germany, Nov. 9, 1961, Sch 30,536 8 (Ilaims. (Cl. 16788) The present invention relates to a hair dyeing method and composition. More particularly, the present invention is concerned with imparting a violet color or tinge to hair, for instance in order to shade other color tones such as a frequently undesirable yellow.

The demands which must be met by the coloring components of present day hair dyeing preparations are very extensive. It is desired to obtain intensive color tones and the dyed hair should be color fast even after washing and when exposed to sunlight. Furthermore, the color of the hair should not be affected by acidic after-treatments or exposure to sweat. The coloring components must not be toxic and must not be capable of causing allergies. Furthermore, it is desirable that the coloring components will give to the hair the desired color even without requirin application of oxidizing agents so that mixing of the dyeing composition with such oxidizng agents or application of the latter to the hair will not be required, thus simplifying the dyeing of the hair and avoiding damage of the same which may be caused by the oxidizing agent.

In many respects, violet is an important color since it is the complementary color to the frequently undesirable yellow. Faded and previously blond, yellow-tinged hair can be dyed with violet to a clear silver-white. Furthermore, violet is used as a modifier or nuancing color in combination with other hair dyes. Fashionable hair colors which are predominantly violet or Bordeaux-red require dyes capable of producing an intensive color so that these color tones will be visible even when applied to dark hair.

Dye compositions which were up to now proposed for the above purpose appear to have certain disadvantages such as instability of the hair color when exposed to acid, low solubility, insufficient color fastness or toxicity.

It is therefore an object of the present invention to provide a hair dyeing composition and a method of dyeing hair which will overcome these disadvantages.

It is a further object of the present invention to provide a hair dyeing composition and a method of dyeing hair which will meet requirements such as are described hereinabove, and by means of which a strong and substantially permanent violet color or tint can be imparted to human hair.

Other objects and advantages of the present invention will become apparent from a further reading of the description and of the appended claims.

With the above and other objects in view, the present invention proposes in a method of dyeing hair, the step of applying to hair which is to be dyed a substance selected from the group consisting of 2,6-dioxypyridine and salts thereof.

According to a preferred manner of carrying out the method of dyeing hair according to the present invention, the same comprises the steps of applying to hair which is to be dyed an aromatic amine adapted to be oxidized into a dye and selected from the group consisting of pphenylenediamine, p-toluylenediamine, p-aminophenol, p-amino-N-dimethylaniline, 4-amino-diphenylamine, 4,4- diaminodiphenylamine, 4-amino-4-oxydiphenylamine, mtoluylenediamine, m-phenylenediamine, o-nitro-p-phen- 3,231,471 Patented Jan. 25, 1966 ylenediamine, 2,6-diaminopyridine, 2,3-diaminopyridine and 2,4-diaminophenol, and at least one substance selected from the group consisting of 2,6-dioxypyridine and salts thereof distributed in an inert carrier substance, and an oxidizing agent adapted to oxidize the aromatic amine.

The present invention also contemplates a composition of matter suitable for use in the oxidative dyeing of hair which comprises at least one dye intermediate adapted to be oxidized to form a dye, and at least one substance selected from the group consisting of 2,6-dioxypyridine and salts thereof.

It has been found according to the present invention that a fast blue and violet color which is intensive and acid resistant, can be imparted to human hair by treating hair with a slightly acidic, neutral or slightly alkaline solution, cream or paste which contains 2,6-dioxypyridine or salts thereof. These compounds are colorless per se but will be developed by exposure to the oxygen of the air or by means of a conventional developer such as hydrogen peroxide so as to give to the hair the desired violet color.

The term slightly acidic is meant to denote a pH of between 2.0 and 6.0, the term neutral a pH of between 6.1 and 8.0, and the term slightly alkaline a pH of between 8.1 and 11.0.

Salts of 2,6-dioxypyridine which may be used in place of 2,6-dioxypyridine include 2,6-dioxypyridine hydrochloride, 2,6-dioxypyridine sulfate and 2,6-dioxypyridine phosphate. To the extent to which other acids are capable of forming salts with 2,6-dioxypyridine, such other salts also may be used. Particularly when the dyeing is carried out in an alkaline or slightly alkaline medium it does not matter which salt of 2,6-dioxypyridine is used, as long as, due to the alkaline medium, the free base 2,6-dioxypyridine is formed from such salt.

Dyeing may be carried out with 2,6-dioxypridine or a salt thereof as the only color forming component, or in combination with other dyes or dye intermediates so as to either give to the hair a bluish or violet color, or to use the violet color component as a complementary color to offset the effect of undesirable yellow color tones, or also to modify and produce nuances of any other hair color;

The coloring of human hair which is achieved according to the present invention is highly stable even in an acidic medium. Furthermore, uniform and fast dyeing will be achieved even on hair which comprises portions which are of different qualities.

Other hair dyes which may be used in combination with 2,6-dioxypridine or salts thereof are those belonging to the groups of aromatic amines, aromatic diamines, aminophenols, diaminopenols, diamino-nitrobenz'ens, diphenylamines and diaminopyridines.

Good results were achieved with the combination of 2,6-dioxypridine or salts thereof with p-phenylenediamine, p-toluylenediamine, p-aminophenol, p-amino-N-dimethyl aniline, 4-amino-diphenylamine, 4,4-diamino-diphenylamine, 4 amino 4'-oxydiphenylamine, m-toluylen'ediamine, m-phenylenediarnine, o-nitro-p-pheny-lenediamine, 2,6-diaminopyridine, 2,3-diaminopyridine and 2,4-diaminophenol.

It is a particular advantage of the use of 2,6-dioxypyridine or salts thereof for dyeing hair in accordance with the present invention that the color is developed already by exposure to air, i.e., by oxidation with the oxygen of the air, without requiring application of another oxidizing agent and that it is possible in this manner to avoid the potentially harmful efiect on the hair of applying an oxidizing agent thereto.

The following examples are given as illustrative only of the present invention, without, however, limiting the invention to the specific details of the examples.

Example I 0.3 gram 2,6-dioxypyridine is dissolved in 99.7 grams of warm water. The thus formed solution has a pH of 2.5.

Upon rinsing with the above solution human hair which has an undesirable yellowish or orange color and subsequent drying, the color of the hair will be found to have changed to an appealing silver-white.

Example II 10.0 grams of an amphoteric shanipooing agent of the type lauryl-ethyl-cycloimidinium-1-hydroxy-3-ethylsodium alcoholate-Z-rnethyl-sodium carboxylate and 2.5 grams of 2,6-dioxypridine hydrochloride are dissolved in 87.5 grams of water.

The thus formed solution is adjusted with potassium hydroxide to a pH of 9.0 and heated to 60 C. until the solution becomes clear.

After cooling a foamable dyeing solution is obtained which is used on hair without adding oxidizing agents.

The solution is worked into the wet hair so as to produce a dense foam. After allowing contact with the hair for between and minutes at body temperature, the hair is rinsed and dried.

It will be found that in this manner white hair acquires a blue-violet color which will intensify after a few hours of exposure to air.

I Example 111 An emulsion is formed of 25.0 grams molten cetyl alcohol, 2.0 grams molten cholesterol and 2.0 grams sodium cetylsulfate in 40.0 grams of water of 75 C.

A solution of 2.0 grams of 2,6-dioxypyridine hydrochloride and 1.3 grams of potassium hydroxide in 26.2 milliliters of water is mixed into the still hot emulsion, and thereafter 1.0 milliliter of aqueous ammonia is added and the mixture stirred until cool. The pH of the thus formed cream is 9.5.

50 grams of the above cream are mixed with 20 milliliters of 6% hydrogen peroxide and this mixture is applied to the hair. 7

After allowing the cream to be in contact with the hair at body temperature for minutes, rinsing and drying of the hair, an intensive blue-violet coloration of the hair is obtained. 7

Example IV 1.2 grams of 2,6dioxypyridine hydrochloride, 1.2 grams of p-toluylenediamine sulfate and 0.82 gram of potassium hydroxide are dissolved under heating in 92.78 milliliters of water.

4.9 milliliters of 25 aqueous ammonia are added to the thus formed solution. The pH of the ammonia-containing solution is 10.3.

Dyeing is carried out by mixing 50 milliliters of the last formed solution with 50 milliliters of 6% hydrogen peroxide and applying the thus formed mixture to the hair.

After application of the solution for 30 minutes, rinsing and drying, the color of the hair will be found to be an intensive red-violet.

Example V 1.2 grams of 2,6-dioxypyridine hydrochloride, 1.2 grams p-amino-N-dimethylaniline and 0.6 gram potassium hydroxide are dissolved under heating in 94 milliliters of water. 3.0 milliliters of 25 aqueous ammonia are added. The thus completed solution has a pH of 10.6.

, 80 milliters of the completed solution are mixed with 20 milliliters of 6% hydrogen peroxide, and the thus formed mixture is applied to the hair.

After application for 30 minutes at body temperature and subsequent rinsing of the hair the same will be found to be of intensive blue-violet color.

4 Example VI A solution is formed under heating of 1.2 grams 2,6-

Example VII 1.2 grams of 2,6-dioxypyridine hydrochloride, 1.2 grams of 4,4-diamino-diphenylamine sulfate and 0.8 gram or" potassium hydroxide are dissolved under heating in 93.8 milliliters of water.

3.0 milliliters of 25% aqueous ammonia are added. The thus formed solution has a pH of 10.4.

Upon treating of hair with the thus formed solution in the manner as described in Example V, an intensive blue-violet hair color is obtained.

Example VIII A solution is formed in the manner. described in the preceding examples of 2.0 grams 2,6-dioxypyridine sulfate, 0.8 gram p-toluylenediamine sulfate, 0.8 gram potassium hydroxide and 91.4 grams water. Subsequently 5.0 grams 25% aqueous ammonia are added. The pH of the fin ished solution is 10.8.

50 milliliters of this solution are mixed with 50 milliliters of 6% aqueous hydrogen peroxide and the thus formed mixture applied to the hair.

After application for 30 minutes, rinsing and drying, an intensive red-violet hair color is obtained.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the stand point of prior art, fairly constitute essential character-' istics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A composition of matter suitable for use in dyeing hair, comprising an alkaline carrier material adapted for application to human hair having distributed therethrough a compound selected from the group consisting of 2,6 dioxypyridine, 2,6-dioxypyridine hydrochloride, 2,6-dioxypyridine sulfate and 2,6-dioxypyr1dine phosphate in an amount equal to between about 0.3% and 2.5% of the weight of said composition.

2. A composition of matter suitable for use in dyeing hair, comprising an alkaline carrier material having arpH of between about 8.1 and 11, adapted for application to human hair having distributed therethrough an acid addition salt of 2,6-dioxypyridine in an amount equal to'between about 0.3% and 2.5% of the weight of said composition.

3. A composition of matter suitable for use in dyeing hair, comprising an alkaline carrier material adapted for application to human hair having distributed therethrough an acid addition salt of 2,6-dioxypyr1dine in an amount equal to between about 0.3% and 2.5 of the weight of said composition.

4. A method of dyeing hair, comprising the step of applying to hair which is to be dyed a compound selected from the group consisting of 2,6-dioxypyridine, 2,6-dioxyhydrochloride, 2,6-dioxypyridine sulfate and 2,6-dioxypyridine phosphate.

5. A method of dyeing hair, comprising the step of applying to hair to be dyed in an alkaline medium having a pH of between about 8.1 and 11 and adapted for application to human hair an acid addition salt of 2,6- dioxypyridine.

6. A method of dyeing hair comprising the steps of applying to hair to be dyed a carrier substance having distributed thereto an effective amount of a compound selected from the group consisting of 2,6-dioxypyridine, 2,6-dioxypyridine hydrochloride, 2,6-dioxypyridine sulfate and 2,6-dioxypyridine phosphate; allowing said compound to remain in contact with the hair for a time suflicient to cause dyeing of the hair; rinsing the thus dyed hair; and drying said hair.

7. A method of dyeing hair comprising the steps of applying to hair to be dyed a carrier material having a pH of between about 8.1 and 11, and adapted for application to human hair having distributed thereto an effective amount of an acid addition salt of 2,6-dioxypyridine; allowing said salt to remain in contact with the hair for a time sufiicient to cause dyeing of the hair; rinsing the thus dyed hair; and drying said hair.

8. A method of dyeing hair comprising the steps of applying to hair to be dyed a carrier substance adapted for application to human hair having distributed thereto an effective amount of an acid addition salt of 2,6-dioxypyridine; allowing said salt to remain in contact with the hair for a time sufficient to cause dyeing of the hair; rinsing the thus dyed hair; and drying said hair.

References Cited by the Examiner UNITED STATES PATENTS 6/1939 Lehmann 16788 OTHER REFERENCES Kass: Am. Perf. and Aromatics, 68: 2, August 1956, 34-37.

Kass et al.: J. Soc. of Cosmetic Chem., 12: 3, April 1961, pp. 146-54.

Kinmont et al.: J. Soc. Cosmetic Chem., 15: 1, 1964, pp. 3-32, especially page 8.

Maier-Bode et a1.: Das Pyridine and Seine Derivate, 1934, pages 143-4.

JULIAN S. LEVITT, Primary Examiner. 

4. A METHOD OF DYEING HAIR, COMPRISING THE STEP OF APPLYING TO HAIR WHICH IS TO BE DYED A COMPOUND SELECTED FROM THE GROUP CONSISTING OF 2,6-DIOXYPYRIDINE, 2,6-DIOXYHYDROCHLORIDE, 2,6-DIOXYPYRIDINE SULFATE AND 2,6-DIOXYPYRIDINE PHOSPHATE. 